Re: Positrons

Den 06.07.2025 06:27, skrev Bertietaylor:

On Sat, 5 Jul 2025 19:43:23 +0000, Stefan Ram wrote:
 

>
  The positron turned out to be pretty useful. Just look at the PET
  (Positron Emission Tomography) scanner. There's a lot of solid proof
  that PET scanners have helped save lives by letting doctors spot
  how diseases are moving along and see if treatments are working.

 Checked that out. Looks like it works on radioactive injections and
consequent radiation. > Nowhere is it said that positrons are radiated
like say beta rays.

In the case of cancer diagnosis a drug containing Fluorodeoxyglucose
is injected into the bloodstream of the patience.
Fluorodeoxyglucose contains F-18, which decay via β+ decay.
F-18 with 9 protons and 9 neutrons →
O-18 with 8 protons and 8 neutrons + positron + neutrino
When the ejected positron hits an electron somewhere in the body,
they annihilate and two gamma particles (photons) are created.
   e⁺ + e⁻  →  γ + γ
Energy and momentum are preserved.
The energy equivalence of an electron and a positron is 0.511 MeV,
so the energy of each of the gamma particles is 0.511 MeV. (0.024 Å)
(Mass is converted to pure kinetic energy of photons)
These gamma particles are detected by two detectors so a 3D image
is created. Because cancer cells have a higher metabolic rate than
do typical cells, they will appear as bright spots in the image.

 Simply calling it pet does not prove the existence of positrons.
 

Right!
But so does the fact that Positron Emission Tomography scanners work.
-- Paul
https://paulba.no/